1. Field of the Invention
The present invention relates to aircraft surface guidance systems (SGS) and, in particular, to a communications interchange for transmitting airport map data to a display system on an aircraft.
2. Technical Background
There is considerable interest in enhancing the field surface guidance for aircraft. After an aircraft lands on a runway at an airport, the next step is to taxi the aircraft to a desired destination such as a passenger loading/unloading gate. A pilot can easily become confused or lost amid the many runways, taxiways, ramps, and buildings that make up an airport. The problem is more significant at large airports and is particularly significant at night when the multitude of lights can make it more difficult to taxi the aircraft to the desired destination.
Efficient taxi operations save time and money. With airports becoming more crowded, aircraft often spend considerable time taxiing between runways and gates. Taxi time is even longer if the pilot makes a wrong turn, becomes lost, or blunders onto the wrong runway or taxiway. In addition, a wrong turn or navigation blunder can cause delays for other aircraft at the airport.
A main feature of an airport surface guidance capability is the presentation of an airport map that is readily available to the pilot. One conventional approach to present such a map is on a head-down display (HDD) that is displayed in the forward field of view of the pilot. The pilot typically enters or selects a taxi path that has been approved by ground controllers. The airport map then indicates the current aircraft position and the taxi path is shown overlaid on the airport map. The map gives a pilot situational awareness of where the aircraft is relative to the taxi instructions. A key aspect to a practical avionics implementation for surface guidance must generally include a communications bus or data link for transmitting the large amounts of data typically required to adequately represent an airport map on a display screen.
An obstacle for the practical implementation of an airport map system is the requirement to clearly display an airport map, preferably with taxi paths and current aircraft position overlaid on the map. Prior avionics systems have attempted to display airport maps by storing the airport map as a digital picture. While this approach works, representation of the airport map in this manner requires large amounts of memory for each airport. A digital representation of an airport map can consume more than one gigabyte of memory. In addition, such digital maps require a correspondingly high speed communications bus to transmit the map data to a display system. This requirement, coupled with the fact that many avionics systems have limited data storage capability and do not have high speed buses, have stymied efforts to implement airport maps on many aircraft. Another approach for displaying airport maps has been to upgrade aircraft avionics systems with new equipment that has large data storage capability and high speed data buses. However, these systems must be designed, certified, integrated with the exiting avionics suite, and installed. All this makes such an upgrade very costly and, therefore, this approach is economically infeasible for many aircraft.
Any airport map system should be adequate not only to accomplish the task of displaying airport maps, but to also make the maps useful and cost-effective. It is also desirable to design a map system that may be retrofit into existing aircraft avionics systems.
The continuing goal, therefore, is to find ways to reduce costs, reduce taxi errors, reduce taxi time, and improve airport efficiency.
To address the goals stated above and other goals, the inventive airport map display system comprises a unique data interchange method for facilitating the communication of airport map data through existing data buses without the need to design or install new high speed data buses. The airport map display system of the current invention also translates map data into a scale that is more user friendly on certain existing display systems. When the invention is implemented using a raster type display system for displaying the airport map data, the vector group labels are redefined to display airport map symbology as opposed to enroute symbology. For retrofit applications, the airport map display system is activated responsive to a preexisting dual use input activated when a taxi-related page is being displayed.
According to one aspect of the present invention, the airport map display system is integrated as an extension of the flight management system (FMS) which provides the enroute planning function for the aircraft. FMSs are already installed in many aircraft and an FMS comprises many of the components required to implement the airport map display system of the invention. For example, an FMS may comprise a processor, data storage devices, a user interface, and is typically in communication with multiple display systems.
In another aspect of the present invention, the airport map data is translated into a scale that is compatible with a target display system. In this manner, the airport map display system of the invention is compatible with a larger selection of preexisting display systems.
Yet another aspect of the invention is the manipulation of raster display interfaces of existing systems by redefining the vector group labels to facilitate the display of airport map symbology.
It is clear that the invention is a significant improvement over the prior art systems. Further, those skilled in the art will recognize that the invention is not limited to use with an FMS. It should be appreciated that other processors, display screens, and data entry devices may be used to practice the present invention.
Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described in the detailed description which follows, the claims, as well as the appended drawings.
It is to be understood that the foregoing description is exemplary of the invention only and is intended to provide an overview for the understanding of the nature and character of the invention as it is defined by the claims. The accompanying drawings are included to provide a further understanding of the invention and are incorporated and constitute part of this specification. The drawings illustrate various features and embodiments of the invention which, together with their description serve to explain the principals and operation of the invention.